The Japanese Meteorological Agency said tsunami waves had already been observed off-shore near the area of Iwaki within six minutes after the quake. Waves were expected to grow as they hit land, the agency said.

At 6:50 a.m. local time, a magnitude-5.0 aftershock was recorded off of Fukushima prefecture.

In Tokyo, about three hours away, people reported several minutes of shaking. Information about damage was not immediately available.

The NHK building still rocking 2 min after quake…

— Robert Speta (@robertspeta)

In 2011, a magnitude-9.0 earthquake rocked the Fukushima region — the largest to ever hit Japan. Around 20,000 people were killed, and 30-foot waves damaged nuclear reactors.

Following Tuesday’s quake, TEPCO, the operator of the Fukushima nuclear plant, said they had so far observed no irregularities.

“We are currently checking the effect on the equipment by this earthquake,” the company said.